SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af507404bfa7e6642ebef7b5b110732e42d147ebc200632768ee31d5b842b18d' 
  AND token = 'JgvPbWDltJf+XhIS03QI+ACfU0R1fKEDyoAyFtAe6oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}