SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76c185dcbbf670215e4abe0e9f877dfb2bb2c6c71fd15c42f3319de88dcf0ad9' 
  AND token = '5sXVnBvC/uRp5jBIxQ+qNM00Tsrc0miqNTjKSnr9h1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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