SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b00d4235542d5c056d43d0aab0564d6595a770a2d413ff4789d15f7e824dd0' 
  AND token = 'q/JCAe/hge3vD+G7Xq4wUBXsDt14orYHnQYFRmiPhKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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